ZHCSH33Z September 1997 – April 2025 LM317
PRODUCTION DATA
The capacitor C1, in combination with the PNP transistor, helps the circuit (Figure 8-13) to slowly start supplying voltage. In the beginning, the capacitor is not charged. Therefore, the output voltage starts at VC1+ VBE + 1.25V = 0V + 0.65V + 1.25V = 1.9V. When the capacitor voltage rises, VOUT rises at the same rate. When the output voltage reaches the value determined by R1 and R2, the PNP is turned off.